Speedometer issue Ford F350

I have a 2000 Ford F350 crew cab long bed diesel 7.3 liter. I posted a question yesterday. I have 133000 miles on it. The speedo went out about a month ago. It has an auto transmission and is 2wd. The OD light is blinking. The cruise and odometer also went out when the speedo did. It was plugged in to a system that gave the code for a vehicle speed sensor. I replaced the speed sensors as well as the abs sensor on the rear diff. Still nothing. I took it to another place, they said it had good signal from the speed sensors to the PCM, but was losing the signal somewhere after that. I wrote yesterday and was recommended to unplug the 2 prong wires that go into the brake master cylinder. I did that and drove it. No change except now the brake light is illuminated on the dash. What else could it be? The PCM?